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Explosion coulombienne de H2 induite par une impulsion laser intense sub-10 fs

Abstract : This work presents an experimental and theoretical study of the interaction of H2 with an intense sub-10fs-laser pulse. The ejection of the two electrons of the molecule by the laser pulse leads to the fragmentation of the physical system in two protons. This process is called Coulomb Explosion. The electronic and nuclear dynamics can be analyzed by measuring the kinetic energy spectra as a function of different laser parameters. This dynamics is also analyzed through a non-perturbative, double active electron theoretical model, based on the resolution of the time dependent Schrödinger equation. In this model, the internuclear distance is treated as a quantum variable.

The experimental and theoretical results underline the translation of the kinetic energy spectra towards a higher energy when the pulse duration decreases. Experimentally, laser pulses from 40 to 10fs were used and down to 1fs using theoretical simulations. This study shows that, for laser pulses shorter than 4fs, the carrier envelope phase becomes a crucial parameter. Furthermore, the molecular dynamics of H2 in intense laser field is sensitive to the peak intensity of the pulse. The experimental and theoretical results show that, as the intensity increases, the kinetic energy spectra are centered around a higher energy. In addition, the presence of two double ionization regimes is theoretically demonstrated for a pulse duration of 4fs. The H2 molecule is also sensitive to the temporal shape of the laser pulse. This sensitivity allows for the detection of pre- or post-pulses by measuring the experimental kinetic energy spectra. Finally, the different double ionization processes are studied. The results show that the electron rescattering influences the femtosecond nuclear dynamics.
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https://tel.archives-ouvertes.fr/tel-00154533
Contributor : Sébastien Saugout <>
Submitted on : Thursday, June 14, 2007 - 9:29:29 AM
Last modification on : Friday, March 5, 2021 - 3:00:53 PM
Long-term archiving on: : Thursday, April 8, 2010 - 5:29:18 PM

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  • HAL Id : tel-00154533, version 1

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Sébastien Saugout. Explosion coulombienne de H2 induite par une impulsion laser intense sub-10 fs. Physique Atomique [physics.atom-ph]. Université Paris Sud - Paris XI, 2006. Français. ⟨tel-00154533⟩

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